Shaft seal



May 12, 1964 c. P. KoLTHoFF, JR., ETAL 3,132,868

SHAFT SEAL Filed Oct. 2. 1961 PMO-W United States Patent() M 3,132,868SHAFT SEAL C. Paul Kolthol, Jr., Naperville, and David A. Cobb,Riverdale, Ill., assignors t International Harvester Company, Chicago,Ill., a corporation of New Jersey Filed Oct. 2, 1961, Ser. No. 142,378 2Claims. (Cl. 277--153) This invention relates lto iiuid seals, and moreparticularly tothe type of seal which prevents iluids from ilovvingaxially .along a shaft through a clearance opening in a housing.

Prior art devices which have Ibeen used for this purpose have usuallyconsisted of a plurality of parts, some of which were fitted onto theshaft, thus requiring extensive machining. Due to the use of a largenumber of parts, many prior art devices have proven Ito lbe difficult toassemble and reassemble, fupon replacing broken or Worn ont parts. Otherprior art devices contain specially molded resilient sealing elements,which necessitate a rather complicated and expensive manufacturingprocess. lt is therefore the general purpose of this invention toprovide a seal which has all the advantages of prior art devices, whilebeing of simpler construction, thereby obvi- -ating manufacturingdiihculties, and difliculties in assembling and reassembling 4thedevice.

It is a further object of the invention to provide an effective sealwhich contains only two vvorking parts.

Another object of the invention is to provide a shaft seal with aself-lubricating sealing element.

Other objects and advantages will become more apparent from thefollowing specification and drawings in which:

FIGURE 1 is a section view of one embodiment of the invention, and

FIGURE 2 is a detail view of the spring element of .FIGURE 1, and

FIGURE 3 is a section View taken along line 3 3 of FIGURE 1, and

FIGURE 4 is a section view of lanother embodiment of the invention, and

FIGURE 5 is a detail View of the spring element of FIGURE 4.

Referring now more specifically to the drawings, ref erence numeralindicates generally a housing having a bore -11 extending therethrough.Shatt 12 is rotatably mounted in bore '11 and is of such a sibe [toallow a substantial amount of clearance between the periphery oftheshaft and the wall of the bore.

The shaft seal is mounted in the clearance area between rth-e shaft andthe housing bore wall, and consists generally of a cylindrically shaped`sleeve member 18 substantially surrounding .a coil spring reinforcingelement 13. In the embodiment shown in FIGURE 1 spring element 13 hasend portions 14 of largest diameter, and central portion 16 of smallestdiameter. Elastic sleeve element 18 is disposed within spring element13, and has its end portions 19 and 20 stretched .around end portions 14of spring element 13. It will readily be appreciated that spring element13, at its portion of smallest diameter 16, urges sleeve element 18 intosealing engagement with shaft 12, thereby preventing iluids from flowingat an area adjacent to the shaft. Sleeve end portions 19 and 20 areurged into sealing engagement with the wall of bore 11 by the endportions 14 of spring element 13, thereby preventing lluid from flowingat an area adjacent the bore wall.

Although it is not essential Ito the operation of the 3,132,868 PatentedMay 12, 1964 ICC seal, in cert-ain applications itV may be desirable toprovide means which locate the seal at a denite point within thehousing. In such an application end por-tions 19 and 20 of sleeve 18 maybe seated in ya peripheral groove 17 in bore Wall 11, thereby preventingthe seal from moving axially in said housing.

In the embodiment illustrated in FIGURE 4, la modilied form ofreinforcing element l13 is shown. Reinforcing element 13 has an endportion 14 of largest diameter, a central portion 15 of intermediatediameter, and an end portion 16 of smallest diameter. Sleeve element 18cooperates with spring element 13 in :the same manner as in theembodiment shown in FIGURE '1, that is, end portions 19' and 20 of ythesleeve are stretched over the coil spring element end portions 14 and16' so as to form a lip substantially enveloping said coil end portions.This embodiment provides for a more flexible seal, because coil portion14 of largest diameter is axially spaced farther from coil portion 16'of smallest diameter than in the embodiment illustrated in FIGURE 1. Inorder to provide Ifor an even greater amount of llexibility, theindividual turns of intermediate coil portion 15 may be spaced apartfrom one another, rather than bein-g closely adjacent or touching, as isshown in FIGURE 5.

Sleeve members 18 iand 18 are formed preferably of a self-lubricatingthermoplastic material, such as nylon or Teflon (trademark owned by E.I. Du Pont de Nemours and Company). l'Ihe self-lubricatingcharacteristics of polyamid materials such as nylon, are well known inthe art. The Tellen resins ane believed to be of thepolyteftnailuoroethylene type described in U.S. Patent #2,230,654 to R.I. Plunkett. A particularly desirable feature of the present inventionis that sleeve member 18 may be formed from a Ilength of tubing,obviating the necessity of forming the sealing element from a specialmolding, as was required in prior art seals. The invention alsocontemplates the use of other well known resilient oil resistantmaterials, such as, neoprene or the like.

Operation of the shait seal should be clearly understood from theforegoing description. l-t should likewise be understood that theinvention has ybeen described in its preferred embodiments only, and'that modifications may be made therein without departing from fthespirit of the invention or the scope of the `appended claims.

What is claimed is:

1. In a uid seal of the type including a housing having a circularopening fonmed therein and a rotatable shaft extending through saidopening, wherein the improvement comprises;

a llexible coupling for preventing passage of liuid between the shaftand opening but permitting relative movement therebetween including,

an elongated coil spring the end portions of which are of a largerdiameter than the diameter of said circular opening, said elongated coilspringy having a central portion located between said end portions andbeing of smaller diameter than said end portions,

an elastic generally cylindrically shaped sleeve member having anunstressed diameter smaller than the diameter of said circular openingformed in said housms,

said sleeve member being disposed within said elongated coil spring andhaving its end portions stretched over said end potrions of said coilspring Iforming lips enveloping said coil spring,

said end portions of said coil spring Ibeing positioned to urge saidlipsAinto sealing engagement with the References Cited in the leof thispatent circular opening in said housing and said central UNITED STATESPATENTS section of said coil spring vbeing posi/Lioned to urge Y saidsleeve into sealing engagement iwih said shafft. 2,580,546 Hotfson Jan 11952 2. The improvement as set forth in claim 1 wherein 5 7441772Amuault et al- May 8, 1956 said circular opening formed in the housingincludes FOREIGN PATENTS groovesrforming seats for said exible couplingto prevent axial movement within said Circular opening. 923,534 France----A Feb- 17, 1947

1. IN A FLUID SEAL OF THE TYPE INCLUDING A HOUSING HAVING A CIRCULAROPENING FORMED THEREIN AND A ROTATABLE SHAFT EXTENDING THROUGH SAIDOPENING, WHEREIN THE IMPROVEMENT COMPRISES; A FLEXIBLE COUPLING FORPREVENTING PASSAGE OF FLUID BETWEEN THE SHAFT AND OPENING BUT PERMITTINGRELATIVE MOVEMENT THEREBETWEEN INCLUDING, AN ELONGATED COIL SPRING THEEND PORTIONS OF WHICH ARE OF A LARGER DIAMETER THAN THE DIAMETER OF SAIDCIRCULAR OPENING, SAID ELONGATED COIL SPRING HAVING A CENTRAL PORTIONLOCATED BETWEEN SAID END PORTIONS AND BEING OF SMALLER DIAMETER THANSAID END PORTIONS, AN ELASTIC GENERALLY CYLINDRICALLY SHAPED SLEEVEMEMBER HAVING AN UNSTRESSED DIAMETER SMALLER THAN THE DIAMETER OF SAIDCIRCULAR OPENING FORMED IN SAID HOUSING,